Terahertz Spectral Analysis Of Bisphenol Derivatives And Signal Transmission Modulation Research

Terahertz has been developed and applied in more and more fields due to its safety,sensitivity,coherence,transient and bandwidth.Among them,the non-invasive non-destructive detection of materials by terahertz technology and the development of terahertz wave modulation devices are two current research hotspots.In this paper,the terahertz time-domain spectral information analysis of four bisphenol derivatives was completed and based on chemical doping method,the terahertz spectral signal modulation was realized.Firstly,it briefly introduces the development history,development status and development prospects of terahertz science and technology.Secondly,the transmission time domain spectroscopy system is introduced,and the classical optical parameter extraction method of the system is calculated and derived.This paper focuses on new spectral interpretation methods and signal transmission regulation:At first,tablet samples of four kinds of bisphenol derivatives?bisphenol A,bisphenol AF,bisphenol E,bisphenol S?were prepared,and the terahertz time domain spectral signals of the samples were obtained by a terahertz time domain spectrometer.The spectral signals in the range of 0.5-2.5 THz are obtained by Fourier transform,and the absorption spectra of the four substances are calculated based on the B3LYP and WB97XD functions of density functional theory.The relationship between the characteristic absorption peaks and the molecular vibration is established.Principal component analysis was performed to find the two associated frequencies:the first group of variance was 0.01575.The second group of variance was0.00736875.These two frequencies not only classify these bisphenol derivatives into the same type of harmful substances,but also provide a new method for the characterization and detection of substances.The above work mainly used spectral analysis to extract effective information.We also studied the terahertz signal transmission modulation devices based on chemical doping method,and strived to improve the performance of the terahertz spectroscopy system itself.PEDOT/PSS films with different HNO₃ doping concentrations and graphene films with different HNO₃soaking time were prepared.The relationship between film transmittance and conductivity was studied based on transmission line circuit theory.At the same time,the Drude model was applied to explore the changes of conductivity mechanism.It was found that 2%HNO₃ doped PEDOT/PSS and graphene soaked HNO₃ 20 min had the best modulation performance,mainly related to the strong screening effect of HNO₃ on PEDOT/PSS and the p-doping effect of HNO₃on graphene.Finally,the performance optimization of carcinoembryonic antibody protein bio-detector was studied based on the novel two-dimensional nanoparticles MoS₂.It was found that MoS₂can promote the effective response of terahertz spectroscopy to carcinoembryonic antibody protein and achieve the effect modulation of terahertz signals of biological macromolecules.The surface of the substrates was modified with MoS₂ nanoparticles.The large specific surface area of MoS₂ was used to load and adsorb more protein molecules.Experiments showed that the bio-detector based on MoS₂ had higher sensitivity to protein concentration,and achieved label-free detection of cancer embryo antibody protein.This study lays an important foundation for the qualitative and quantitative detection of terahertz technology for cancer tumor markers.